fix: modernize Hole.pm preamble and fix POD typos

lib/Safe/Hole.pm

@@ -3,22 +3,18 @@
 # This program is free software under the GPL.
 package Safe::Hole;
 
-require 5.005;
+use 5.014;
 use Carp;
 use strict;
-use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);
+use warnings;
 
 require Exporter;
 require DynaLoader;
 
-@ISA = qw(Exporter DynaLoader);
-
-# Items to export into callers namespace by default. Note: do not export
-# names by default without a very good reason. Use EXPORT_OK instead.
-# Do not simply export all your public functions/methods/constants.
-@EXPORT = qw(
-);
-$VERSION = '0.15';
+our @ISA       = qw(Exporter DynaLoader);
+our @EXPORT    = qw();
+our @EXPORT_OK = qw();
+our $VERSION   = '0.15';
 
 bootstrap Safe::Hole $VERSION;
 
@@ -178,15 +174,15 @@ Safe::Hole - make a hole to the original main compartment in the Safe compartmen
 using share(), or can call methods through the object that is copied
 into the Safe compartment using varglob(). But that subroutines or
 methods are executed in the Safe compartment too, so they cannot call
-another subroutines that are dinamically qualified with the package
+another subroutines that are dynamically qualified with the package
 name such as class methods nor can they compile code that uses opcodes
 that are forbidden within the compartment.
 
   Through Safe::Hole, we can execute outside defined subroutines in the 
 original main compartment from the Safe compartment. 
 
   Note that if a subroutine called through Safe::Hole::call does a
-Carp::croak() it will report the error as having occured within
+Carp::croak() it will report the error as having occurred within
 Safe::Hole.  This can be avoided by including Safe::Hole::User in the
 @ISA for the package containing the subroutine.
 
@@ -209,7 +205,7 @@ Class method. Constructor.
 constructor arguments.  The argument ROOT specifies the alternate root
 namespace for the object.  If the ROOT argument is not specified then
 Safe::Hole object will attempt restore as much as it can of the
-environment in which it was constrtucted.  This includes the opcode
+environment in which it was constructed.  This includes the opcode
 mask, C<%INC> and C<@INC>.  If a root namespace is specified then it
 would not make sense to restore the %INC and @INC from main:: so this
 is not done.  Also if a root namespace is given the opcode mask is not
@@ -218,7 +214,7 @@ restored either.
 =item call $coderef [,@args]
 
 Object method. 
-  Call the subroutine refered by $coderef in the compartment that is
+  Call the subroutine referred to by $coderef in the compartment that is
 specified with constructor new. @args are passed as the arguments to
 the called $coderef.  Note that the arguments are not currently passed
 by reference although this may change in a future version.
@@ -261,7 +257,7 @@ may still be a way that the authors have not considered.  In
 particular it relies on the fact that a Perl program cannot change
 stuff inside the magic on a Perl variable.  If you install a module
 that allows a Perl program to fiddle inside the magic then this
-assuption breaks down.  One would hope that any system that was
+assumption breaks down.  One would hope that any system that was
 running un-trusted code would not have such a module installed.
 
 =head1 AUTHORS